Surging and Unsettled Idel after MPS Rebuild, '74 2.0L D-Jet Options

[914four]

Running down a bucking issue and found my MPS to be leaking. After rebuilding the MPS and verifying a good seal, everything went back together okay. When I started the car, the engine surged up and down and would not idle.

The electrical connector socket on the MPS does not appear to be keyed and using the diagram below from Clay's D-Jet troubleshooting guide it seems I may have plugged in the MPS wire incorrectly. I ohmed the wires from the ECU connector to the MPS socket and made sure the wires are in the order shown in the diagram.

The wires look to be looping back from terminal 7 to 15 and 8 to 10 so that the socket could be plugged in either way and work correctly. Could plugging in the MPS wires incorrectly have damaged the ECU? If not, what should I be looking for that would cause the surging and lack of idle?

[zambezi]

What would you recommend for a good tester to test the CO. And where should the probe be placed? Is a tailpipe probe good enough or should a dedicated O2 bung be welded into the exhaust pipe (and where)? I will need to fine tune my fuel system as well and am trying to plan it all out now so it does not take me weeks to get good results.

[pbanders]

What would you recommend for a good tester to test the CO. And where should the probe be placed? Is a tailpipe probe good enough or should a dedicated O2 bung be welded into the exhaust pipe (and where)? I will need to fine tune my fuel system as well and am trying to plan it all out now so it does not take me weeks to get good results.

There are probably others here with more experience than me in fitting a wide-band AFM to your 914, with recommendations. Hopefully, someone will see this and comment, otherwise, you might want to start a new topic.

The way I'm doing it with my car is that I have a Heathkit Emissions Tester that I bought and built probably 30 years ago. It still works great and has always correlated well when I've compared it to my emissions test results, and I can actually use it while driving, so I can determine my part and full-load mixtures. The Heathkit is NLA, you see them on Ebay from time to time. There are a number of similar standalone CO testers, look on Google and Amazon.

Another way you can do this is to find a tuner shop with a dyno and shop-quality emissions gear. Most places charge something on the order of $100 to $200 to do a test run on your car. This approach offers you the possibility of tuning your MPS on-the-fly, and can duplicate all running conditions.